Assistance needed to write this program urgently

Write a C++ program that takes an STL vector of int values and determine if all the numbers are different from each other (that is, they are distinct). The first line will be the size of the vector followed by actual elements. Sample I/O 1: Input: 6 5 9 8 7 6 4 Out put: true Sample I/O 2: Input: 6 5 9 8 7